This invention relates generally to detection, in situ, of damaged rotor vanes or blades; more particularly it concerns method and apparatus for quickly accessing and viewing a sequence of vanes or blades within the turbine or other section of a rotary engine, without requiring costly disassembly of the engine, for the purpose of determining whether or not a damaged vane or blade exists. If it does exist, expensive inflight engine failures can be prevented by early detection of distressed vanes or blades.
It is found in the operation of rotary engines, such as jet engines, that certain vane or blade elements can and do become damaged by overheating, whereas others remain undamaged. Thus, for example, hot spots can occur in the front stator vane stage rearward of the combustion zone, due to undesired local migration of combustion areas rearwardly to that stator vane stage. As a result, overheating and damage of a stator vane or vanes can occur, leading to eventual burn through of the vane, with resulting engine failure. In the past, such damage frequently remained undetected until engine disassembly or engine failure. No way was known to positively detect the existence and extent of damage to such vanes, without costly engine overhaul or disassembly.